1. Field of the Invention
The present invention relates to a power switchgear and particularly to electrodes configurations for the switchgear.
2. Description of the Related Art
A gas insulated switchgear includes a power switchgear, such as a breaker, a disconnector, and an earthing switch, and a bus bar. The breaker interrupts fault current, the disconnector energizes/de-energizes an electrical circuit, and the earthing switch connects a device to the ground. The bus bar, having a high-voltage conductor in its inside, extends to a transformer. A failed gas insulated switchgear could lead to a problem, such as blackout, with an energy transmission and transformation system. Thus, gas insulated switchgears of high reliability are being called for.
The gas insulated switchgear has the switchgears of various types as described above, the switchgears being provided with a great number of sliding portions at their mechanism portions and contact parts. The bus bars are separated via a sliding portion. At a time of absorbing a displaced portion resulting from heat shrinkage or an earthquake, the sliding portion absorbs the displaced portion. Such a sliding portion is required to have sliding characteristics such as small frictional force and little abrasion amount and be able to prevent gradation and reduction of a lubricant and diffusion of a degradable living substance between electrodes of a disconnector.
To maintain for a long period of time such a condition that a sliding portion has a small frictional force and a low depth of wear, the conventional gas insulated, switchgear disclosed in JP-2011-147217-A is configured as follows. A movable contactor has a hard, carbon film on its circumferential surface except following two areas: one that is in contact with a contact, terminal of a stationary-side contact part, while a movable-side contact part is inserted into the stationary-side contact part to be electrically connected; and another that is in contact with a contact terminal of the movable-side contact part while the movable-side contact part and the stationary-side contact part are electrically disconnected.